The invention relates to a closure for a container to be pressurised, comprising a housing to be fixed to the container, in which a passage is present, whilst a seat is arranged in said passage, which seat is intended to mate with a closing element, which is urged in the direction of the seat by means of a coil spring surrounding said closing element, said coil spring being confined between a part of the closing element and a few spaced-apart projections formed in one piece with the housing, which are connected to the remaining part of the housing by means of a few spaced-apart arms, said coil spring and said projections being capable of resilient deformation relative to each other, in such a manner that the spring can be moved past the projections in its position of use.
Such a closure is known from U.S. Pat. No. 3,939,860. In said known construction, the arms and the projections formed on the lower ends of the arms are separated from each other by gaps extending between said arms.
The projections support a ring, on which the lower end of the spring is supported. In order to prevent undesirable pivoting of the arms, a ring is arranged round the ends of the arms, which ring is accommodated in grooves formed in the ends of the arms.
According to the invention, the closure is provided with two diametrically opposite projections formed on the inner circumference of a ring-shaped element being in one piece with said projections, which ring-shaped element is connected to the remaining part of the housing via two diametrically opposite arms located between the projections, seen in the direction of the central axis of the housing, whilst one end of the spring is directly supported on said projections.
By using the construction according to the invention, a closure of simple design can be obtained, which is built up of fewer individual parts than the closure which is known from U.S. Pat. No. 3,939,860 and which is easy to fit.
It is noted that from WO 99/07632 there is known a closure in which a coil spring surrounding the closing element is accommodated in a housing, which housing is provided with a flange at its bottom end for supporting the lower end of the spring. One drawback of this construction is the fact that a special tool must be used for fitting the spring, which tool is to deform the spring in such a manner that it can be placed into the housing via the passage formed in the housing, which can be closed by means of the closing element.
With the closure according to the invention, the fitting of the coil spring is further facilitated in that the facing boundary surfaces of the projections slope upwards from their free ends in the direction of the seat over part of their height.
The use of a coil spring having a conical configuration, in which the winding at the end of the coil spring remote from the seat is the largest winding of the coil spring, makes it possible to introduce at least a large part of the coil spring into the space present between the arms without there being a need to deform the ring-shaped element and the projections supported by said ring-shaped element.
A proper guidance of the closing element is obtained in that the closing element is provided with a shell-shaped member surrounded by the coil spring, which member includes a flange which is slidably accommodated with a tight fit in the ring-shaped element.
When the shell-shaped member is provided with a flanged collar at its end facing towards the seat, said shell-shaped member can also be utilised for supporting one end of the coil spring.
Partially on account of the conical configuration of the coil spring, the coil spring is easy to fit on the closing element, because the coil spring can be moved past the collar onto the shell-shaped member under resilient deformation of at least the coil spring that abuts against the collar in the mounted position of the coil spring.
The invention furthermore relates to a container comprising a housing of a closure present in an opening formed in the container and extending at least partially outside said container and mounted to said container, in which a closing element mating with a seat arranged in the centre of the housing is present, which closing element is accessible via the open upper end of the housing so as to be forced open by a tapping mechanism upon connection of the tapping mechanism to the container.
Such containers, which are generally used for beer or soft drinks, can be derived from Dutch patent applications Nos. 1008828 and 1014078. In these known constructions, the containers are provided with necks closing the openings, which necks are arranged on the outer side of the containers, which necks are generally welded to the container. In these known constructions, the closure is inserted into the container through the open upper end of the neck, and the housing of the closure is secured in position in the neck, for example by means of a threaded connection or by means of a bayonet connection, possibly in co-operation with a locking ring.
The above construction requires a costly machining operation on at least the interior of the neck and the exterior of the housing, so as to ensure a proper connection of the housing to the neck, wherein furthermore provisions rust be made to prevent the closure from moving out of the container unintentionally under the influence of the prevailing pressure in the container.
According to the invention, the housing of the closure is provided with a projecting flange at the end remote from the open upper end of the housing, whose boundary surface facing towards the open upper end of the housing extends at least in part away from said open upper end, seen in the direction of the outer circumference of the flange, wherein said boundary surface of the flange abuts against the inner side of the correspondingly configured wall portion surrounding the opening that is present in the container.
When using the construction according to the invention, the housing of the closure can be passed through the opening in the container from the inside, and the flange formed on one end of the housing will come to abut against the inner wall of the keg. The housing can be fixed to the container by means easy to fit which engage the part of the housing that projects the container, with the flange that abuts against the inner wall of the container preventing the closure from moving out of the container in some way or other under the influence of the prevailing pressure in the container, so that a simple and very safe construction can be obtained.
It is noted that from U.S. Pat. No. 3,228,413 there is known a container which comprises a valve housing containing two valves, which is positioned within the keg in its entirety. An extension piece provided with passages, which is passed through a neck of the container, is attached to said valve housing. The passages in the extension piece are intended for passage therethrough of tappets for actuating the valves. This known construction is complicated and expensive.